{"product_id":"audio-matching-transformer-miniature-output-center-tap-inter-stage","title":"Audio Matching Transformer Miniature Output Center Tap Inter Stage","description":"\u003cp\u003eThis is one item of new, sub-miniature audio transformer commonly used in small, low voltage supply transistor radio audio output stages. Three different types are available; An inter-stage phase splitter, an output phase-combiner and impedance matcher, and an unusual inter-stage device with three separate windings. Power rating is estimated at 150mW. Overall dimensions are 14.3L x 12.5W x 11.3H (mm). Basic test results at 1kHz are shown in the secondary pictures.\u003c\/p\u003e\n\u003cp\u003eThese are largely obsolete for the original intended purpose, but they do have their \"cunning plan\" uses, like obtaining beyond-rail drive from a voltage amplifier stage into a small class B output stage running on a 3V battery supply, without having to resort to boost supplies.\u003c\/p\u003e\n\u003cp\u003eOutput Yellow\u003c\/p\u003e\n\u003cp\u003eThe primary side is the tapped side. This has a D.C. resistance of approximately 10.6 Ohm, and that of the secondary is about 1.8 Ohm. The secondary is intended to drive a small 8 Ohm radio speaker. Ignoring the centre tap, the impedance ratio is about 6.25:1, making the primary impedance 50 Ohms.\u003c\/p\u003e\n\u003cp\u003eInter-Stage 1 Green\u003c\/p\u003e\n\u003cp\u003eWhen used conventionally, the untapped side is the primary side. The primary side has a D.C. resistance of approximately 232 Ohms and the secondary side shows 208 Ohms, 104 Ohms between the centre tap and each outer connection. Ignoring the centre-tap, the impedance ratio is about 2.4:1\u003c\/p\u003e\n\u003cp\u003eInter-Stage 2 Blue\u003c\/p\u003e\n\u003cp\u003eThis type is slightly unusual, as it has two separate secondary windings. The voltage ratio from primary to one secondary is approximately 2:1 giving and impedance ratio of 4:1. The primary has a D.C. resistance of 155 Ohms and each secondary measures around 68 Ohms.\u003c\/p\u003e","brand":"HJW Electronics","offers":[{"title":"Output Yellow","offer_id":58783115739520,"sku":null,"price":2.9,"currency_code":"GBP","in_stock":true},{"title":"Inter-Stage 1 Green","offer_id":58783115772288,"sku":null,"price":2.9,"currency_code":"GBP","in_stock":true},{"title":"Inter-Stage 2 Blue","offer_id":58783115805056,"sku":null,"price":2.9,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/1007\/2136\/1280\/files\/group_angle_s_97243c3a-4453-45a6-ab64-0e7022d8dcba.jpg?v=1787765553","url":"https:\/\/shop.usefulcomponents.com\/products\/audio-matching-transformer-miniature-output-center-tap-inter-stage","provider":"HJW Electronics","version":"1.0","type":"link"}